Orange-serum Agar can be used for the isolation, cultivation and enumeration of acid-tolerant spoilage microorganisms in fruit juice and fruit juice concentrates, in particular from citrus fruit, according to Hays, Troy and Beisel.The prepared agar may be turbid after autoclaving due to orange extract.Orange-serum Agar has been used to prepare modified orange serum (MOS) as a medium for Hymenoscyphus fraxineus.